This group studies how organisms sense environmental signals and transduce the signals into changes in gene expression and cell physiology. The group has continued their characterization of the two regulators central to the Escherichia coli response to oxidative stress: OxyR, a 34 kDa transcriptional activator which is switched on by oxidation, and oxyS, a novel 109 nucleotide RNA regulator which acts as an activator and repressor of gene expression. In addition to studying the mechanisms of OxyR and oxyS action, the group has begun to determine what regulators are important to the response to hydrogen peroxide in Saccharomyces cerevisiae. Using Arabidopsis thaliana as a model system, the group is also characterizing mutants defective in their developmental response to blue light.